In Lok's most recent vlog, he visits Kai's apartment and while Kai is showing off his gear, at some point he mentions that he has a camera on the table that he can't show off due to NDA - probably the same as Casey has in the photo. The timing all seems about right for a Dec 15 announcement - the big question is how disappointed people will be when it only has about 1/4 of the features that they've dreamt up

(Also, here's hoping that it IS a low light GH5 with lots of great video features so that it can push Sony to finally release an A7s3)

Unfortunately due to such moron thing as science it not much you can do to make "low light" GH5.
And Sony A7s fame was most pronounced due to horrible sensor readout in video in first generations of A7 cameras.

I think it can be done.
DP wise with iso of 6400 clean image, we can use it almost on any applications. Yes a quick lens is needed, but nowadays who can't get a t2.0 or 1.5

More than that Iso, personally it is already cool for me. I've shoot on red dragon and weapon on iso 3200 and lots of noise in those sensors. If Alexa can barely pull 6400, and panafriend is able to pull 6400 clean I'm all in.

But with such small pixels with this new Bayer pattern I don't see HDR as a feature on low light.

You can't beat physics on silicon these days. You must use black silicon, or graphene and those techs need to be implemented yet.

If the sensor rumors are true, the new camera would have bigger pixels than the existing gh5 as well as moving to a BSI sensor.

If that all gives another 1-2 stops of light, I'd be glad to call it a low-light GH5. Will it perform the same as the a7s series at the exact same f-stop? Still no, but that's a silly comparison anyway. I get 1 1/3 stop boost on my full frame lenses using a speed booster xl. Even if it's still off a stop compared to the a7s, I'd still probably be inclined to choose it for all of the other advantages.

It would be a bummer to lose ex-tele mode in 4k, though, but that'd be a trade-off I'd take (just like APS-C mode doesn't work in 4k on the a7s mark ii (and it's available, but not really 4k on the original)).

Yeah, you're right VK. Moving to a BSI sensor with larger photosites would probably have minimal or no impact whatsoever on the camera's ability to capture an image with less light. I'm obviously a complete dupe of marketing people for thinking that either of those things would make any difference at all.

It will probably use a dual ISO configuration like the EVA1 if it is based on the same sensor platform. Expect the camera to cost nearly 3k if they want to separate it as a premium product from the plain GH5. It should have the new IBIS from the G9 6.5 stops and the high res shot mode to cope with the lower resolution if 10MP for higher res stills. Both the supposed leaked shots in my view are fake and altered, not from a new camera.